Chemistry-Question-Bank-píginas-7

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CHEMICAL BONDING AND MOLECULAR STRUCTURE 55
27. Among the following the electron deficient compound is
(a) BCl3 (b) CCl4
(c) PCl5 (d) BeCl2
28. Which of the following is the electron deficient
molecule?
(a) C2H6 (b) B2H6
(c) SiH4 (d) PH3
29. Which of the following compounds does not follow the
octet rule for electron distribution?
(a) PCl5 (b) PCl3
(c) H2O (d) PH3
30. A pair of compound which have odd electrons in the group
NO, CO, ClO2, N2O5, SO2 and O3 are
(a) NO and ClO2 (b) CO and SO2
(c) ClO2 and CO (d) SO2 and O3
31. Which of the following statements is incorrect ?
(a) The formation of ionic compounds depend upon the
ease of formation of the positive and negative ions
from the respective neutral atoms.
(b) Formation of ionic compounds depend upon
arrangement of the positive and negative ions in the
solid.
(c) Formation of positive ion involves addition of
electron(s) while that of negative ion involves
removal of electron(s).
(d) None of these
32. Complete the following statement by choosing the
appropriate option.
Ionic bonds will be formed more easily between elements
with comparatively A and elements with
comparatively high negative value of B .
(a) A = low electronegativity
B = ionization enthalpy
(b) A = low ionization enthalpy
B = electron gain enthalpy
(c) A = high ionization enthalpy
B = electron gain enthalpy
(d) A = high electronegativity
B = ionization enthalpy
33. In ionic solids how crystal structure get stabilized
(a) By the energy released in the formation of crystal
lattice.
(b) By achieving octet of electrons around the ionic
species in gaseous state.
(c) By electron gain enthalpy and the ionization enthalpy.
(d) None of these
34. Energy required to completely separate one mole of a
solid ionic compound into gaseous constituent ions is
called .......... .
(a) Ionisation enthalpy
(b) Electron gain enthalpy
(c) Bond dissociation enthalpy
(d) Lattice enthalpy
35. The effect of more electronegative atom on the strength of
ionic bond
(a) increases (b) decreases
(c) remains the same (d) decreases slowly
36. Which of the following combination will form an
electrovalent bond ?
(a) P and Cl (b) NH3 and BF3
(c) H and Ca (d) H and S
37. Among the following which compound will show the highest
lattice energy ?
(a) KF (b) NaF
(c) CsF (d) RbF
38. Which of the following bond will have highest ionic
character?
(a) H–I (b) H–F
(c) H–Cl (d) H–Br
39. Which of the following pairs will form the most stable ionic
bond ?
(a) Na and Cl (b) Mg and F
(c) Li and F (d) Na and F
40. Which of the following methods is used for measuring
bond length ?
(a) X-ray diffraction
(b) Electron-diffraction
(c) Spectroscopic techniques
(d) All of these
41. .......... is measured as the radius of an atom’s core which
is in contact with the core of an adjacent atom in a
bonded situation.
(a) van der Waal’s radius
(b) Bond length
(c) Covalent radius
(d) Ionic radius
42. Following figure represent a chlorine molecule. Identify A
B and C in the given figure.
A
C
B
36
0 
pm
(a) A = Bond length, B = van der Waal’s radius
C = Covalent radius
(b) A = Covalent radius, B = Bond length
C = Ionic radius
(c) A = Ionic radius, B = van der Waal’s radius
C = Covalent radius
(d) A = Covalent radius, B = van der Waal’s radius
C = Bond length
56 CHEMICAL BONDING AND MOLECULAR STRUCTURE
43. Which of the following statement is correct?
(a) Amount of energy required to break one mole of
bonds of a particular type between two atoms in a
gaseous state is called bond enthalpy.
(b) The unit of bond enthalpy is kJ mol–1
(c) Larger the bond dissociation enthalpy, stronger will
be the bond in the molecule
(d) All of these
44. Complete the following statements.
With A in bond order, B increases
and C decreases.
(a) A = increase, B = bond length, C = bond enthalpy
(b) A = decrease, B = bond enthalpy, C = bond length
(c) A = increase, B = bond enthalpy, C = bond length
(d) A = increase, B = bond angle, C = bond enthalpy
45. Which of the following molecules have same bond order ?
2 2 2 2
IIII II IV V
H , Cl , CO, Br , N
Choose the correct option.
(a) I, II and IV have same bond order
(b) III and V have same bond order
(c) Both (a) and (b) are correct
(d) None of the above
46. Which one of the following is not correct representation of
resonance ?
A. :O C O:: :: :
I II III
: : :O C O:: : :: :O C O:: : ::
: : :
:– –+ +. .. .
B.
:O: :O: :O
:O: :O: :O:
:O: :O: O
C C C
I II III:
: :
:
:
: :
–– ––
– –
– :
:
Choose the correct option.
(a) Only A (b) Only B
(c) Both A and B (d) None of the above
47. Which of the following structure represents structure of
O3 more accurately?
O
O O
14
8 p
m
121 pm
O
O O
12
1 p
m
148 pm
I II
O
O O
12
8 p
m 128 pm
III
(a) I (b) II
(c) III (d) I and II
48. Which of the following is/are misconception(s) associated
with resonance ?
(i) The molecule exist for a certain fraction of time in
one cannonical form and for other fractions of time
in other cannonical forms.
(ii) The cannonical forms have no real existence.
(iii) There is no such equilibrium between the cannonical
forms.
(a) (i) only (b) (ii) and (iii)
(c) (i) and (iii) (d) (iii) only.
49. The number of possible resonance structures for 2
3CO is
(a) 2 (b) 3
(c) 6 (d) 9
50. Which one of the following is not the resonance structure
of CO2?
(a) O = C = O (b) – O – C O+
(c) + O C – O– (d) O C = O
51. All the bond lengths of sulphur – oxygen in sulphate ion,
are equal because of:
(a) symmetry
(b) resonance
(c) high electronegativity of oxygen
(d) None of these
52. Resonance is due to
(a) delocalization of sigma electrons
(b) delocalization of pi electrons
(c) migration of protons
(d) Both (a) and (b)
53. Which one of the following pairs of molecules will have
permanent dipole moments for both members ?
(a) NO2 and CO2 (b) NO2 and O3
(c) SiF4 and CO2 (d) SiF4 and NO2
54. The molecule which has zero dipole moment is
(a) CH3Cl (b) NF3
(c) BF3 (d) ClO2
55. Which of the following has dipole moment?
(a) CO2 (b) p-dichlorobenzene
(c) NH3 (d) CH4
56. Identify the non polar molecule in the following compounds
(a) H2 (b) HCl
(c) HF and HBr (d) HBr
57. A neutral molecule XF3 has a zero dipole moment. The
element X is most likely
(a) chlorine (b) boron
(c) nitrogen (d) carbon
58. Among the following, the molecule of high dipole moment
is
(a) CCl4 (b) NH3
(c) H2O (d) CHCl3
59. Which one of the following molecules is expected to have
zero dipole moment?
(a) H2O (b) CO2
(c) SO2 (d) CaF2
CHEMICAL BONDING AND MOLECULAR STRUCTURE 57
60. The correct order of dipole moments of HF, SH2 and OH2 is
(a) OHSHHF 22 (b) OHSHHF 22
(c) OHSHHF 22 (d) SHOHHF 22
61. The most polar bond is
(a) C – F (b) C – O
(c) C – Br (d) C – S
62. Which of the following possess dipole moment SF6(a),
SO2(b), H2S(c) , SF4(d) ?
(a) b and c (b) a and c
(c) b, c and d (d) a and b
S
F
F
F
F
F
F
 S OO
..
 
S
F
:
F
F
F
 S
HH H
63. According to Fajan’s rule, covalent bond is favoured by
(a) Large cation and small anion
(b) Large cation and large anion
(c) Small cation and large anion
(d) Small cation and small anion
64. Arrange the following in increasing order of covalent
character (i) NaCl, (ii) RbCl, (iii) MgCl2, (iv) AlCl3 ?
(a) (i), (ii), (iii), (iv) (b) (iv), (ii), (i), (iii)
(c) (ii), (i), (iii), (iv) (d) (iii), (i), (ii), (iv)
65. The correct sequence of increasing covalent character
is represented by
(a) LiClcontains
(a) polar covalent bond (b) double bond
(c) co-ordinate bond (d) electrovalent bond
70. Sodium chloride is an ionic compound whereas hydrogen
chloride is mainly covalent because
(a) sodium is less reactive
(b) hydrogen is non-metal
(c) hydrogen chloride is a gas
(d) electronegativity difference in the case of hydrogen
and chlorine is less than 2.1.
71. According to VSEPR theory the geometry of a covalent
molecules depends upon
(a) the number of bond pairs of electrons
(b) the number of lone pairs of electrons
(c) the number of electron pairs present in the outer shell
of the central atom
(d) All the above
72. The geometry of –ClO ion according to Valence Shell Electron
Pair Repulsion (VSEPR) theory will be
(a) planar triangular (b) pyramidal
(c) tetrahedral (d) square planar
73. In BrF3 molecule, the lone pairs occupy equatorial positions
to minimize
(a) lone pair - bond pair repulsion only
(b) bond pair - bond pair repulsion only
(c) lone pair - lone pair repulsion and lone pair - bond pair
repulsion
(d) lone pair - lone pair repulsion only
74. Which of the correct increasing order of lone pair of electrons
on the central atom?
(a) IF7 s–s > p–p (b) p–p > s–s > s–p
(c) s–s > p–p > s–p (d) s–s > s–p > p–p
99. Which of the following will have sp3 d3 hybridisation?
(a) BrF5 (b) PCl5
(c) XeF6 (d) SF6
100. The shape of 2CO molecule is
(a) linear (b) tetrahedral
(b) planar (d) pyramidal
101. The hybridisation state of carbon in fullerene is
(a) sp (b) sp2
(c) sp3 (d) sp3d
102. Which of the following statements is true for an ion having
sp3 hybridisation?
(a) all bonds are ionic
(b) H-bonds are situated at the corners of a square
(c) all bonds are co-ordinate covalent
(d) H-atoms are situated at the corners of tetrahedron
103. Which of the following molecule does not have a linear
arrangement of atoms ?
(a) H2S (b) C2H2
(c) BeH2 (d) CO2
104. In which one of the following molecules the central atom
said to adopt sp2 hybridization?
(a) BeF2 (b) BF3
(c) C2H2 (d) NH3
105. Considering the state of hybridization of carbon atoms, find
out the molecule among the following which is linear ?
(a) CH3– CH = CH–CH3
(b) CH3 – C C – CH3
(c) CH2 = CH – CH2 – C CH
(d) CH3 – CH2 – CH2 – CH3
106. Equilateral shape has
(a) sp hybridisation (b) sp2 hybridisation
(c) sp3 hybridisation (d) None of these
107. In an octahedral structure, the pair of d orbitals involved in
2 3d sp hybridization is
(a) 2 2 2,x y z
d d (b) 2 2,xz x y
d d
(c) 2 , xzz
d d (d) ,xy yzd d
108. The trigonal bipyramidal geometry is obtained from the
hybridisation
(a) dsp3 or sp3d (b) dsp2 or sp2d
(c) d 2sp3 or sp3d 2 (d) None of these
109. In which of the following species is the underlined carbon
having sp3 - hybridisation ?
(a) OOHC–CH (b) OHHCCH
(c) OCHCCH (d) CHHCCH
110. A sp3-hybrid orbital contains
(a) 25% s-character (b) 75% s-character
(c) 50% s-character (d) 25% p-character
111. The types of hybridisation of the five carbon atoms from
left to right in the molecule
CH3 — CH == C == CH — CH3 are
(a) sp3, sp2, sp2, sp2, sp3 (b) sp3, sp, sp2, sp2, sp3
(c) sp3, sp2, sp, sp2, sp3 (d) sp3, sp2, sp2, sp, sp3
112. Pick out the incorrect statement from the following
(a) sp hybrid orbitals are equivalent and are at an angle
of 180° with each other
(b) sp2 hybrid orbitals are equivalent and bond angle
between any two of them is 120°
(c) sp3d2 hybrid orbitals are equivalent and are oriented
towards corners of a regular octahedron
(d) sp3d3 hybrid orbitals are not equivalent
113. All carbon atoms are sp2 hybridised in
(a) 1, 3-butadiene (b) CH2 = C = CH2
(c) cyclohexane (d) 2-butene
114. Which one of the following is not correct in respect of
hybridization of orbitals?
(a) The orbitals present in the valence shell only are
hybridized
(b)The orbitals undergoing hybridization have almost
equal energy
(c) Promotion of electron is not essential condition for
hybridization
(d) Pure atomic orbitals are more effective in forming stable
bonds than hybrid orbitals
115. Molecular orbital theory was given by
(a) Kossel (b) Mosley
(c) Mulliken (d) Werner
116. Atomic orbital is monocentric while a molecular orbital is
polycentric. What is the meaning of above statements?
(a) Electron density in atomic orbital is given by the
electron distribution around a nucleus in an atom.
While in molecular orbital it is given by the electron
distribution around group of nuclei in a molecule.
(b) While an electron in an atomic orbital is influenced
by one nucleus, in a molecular orbital it is influenced
by two or more nuclei depending upon the number
of atoms in the molecule.
(c) The electron in an atomic orbital is present in one
nucleus while in molecular orbital electrons are
present on more than one nuclei depending upon
the number of atoms in the molecule.
(d) All of these
117. With increasing bond order, stability of bond
(a) Remain unaltered (b) Decreases
(c) Increases (d) None of these
60 CHEMICAL BONDING AND MOLECULAR STRUCTURE
118. The given increasing order of energies of various
molecular orbitals is not true for which of the following
molecule?
1s Na (b) Nb Ny (b) Nx = Ny
(c) Nx O2
(c) Diamagnetic and Bond order O2
133. Bond order is a concept in the molecular orbital theory. It
depends on the number of electrons in the bonding and
antibonding orbitals. Which of the following statements is
true about it ? The bond order
(a) can have a negative quantity
(b) has always an integral value
(c) can assume any positive or integral or fractional value
including zero
(d) is a non-zero quantity
134. Which of the following does not exist on the basis of
molecular orbital theory ?
(a) H2
+ (b) He2
+
(c) He2 (d) Li2
135. The paramagnetic property of the oxygen molecule is due
to the presence of unpaired electrons present in
(a) 1 1
x x( 2p ) and ( *2p )
(b) 1 1
x y( 2p ) and ( 2p )
(c) 1 1
y z( *2p ) and ( *2p )
(d) 1 1
x z( *2p ) and ( *2p )
136. In which of the following state of compound the
magnitude of H-bonding will be maximum and in which
case it will be minimum ?
(a) Maximum = Solid, Minimum = Liquid
(b) Maximum = Liquid, Minimum = Gas
(c) Maximum = Solid, Minimum = Gas
(d) Maximum = Gas, Minimum = Solid
CHEMICAL BONDING AND MOLECULAR STRUCTURE 61
137. Which of the following are correctly classified ?
Intermolecular Intramolecular
H-bonding H-bonding
(a) HF H2O
(b) CH3OH HF
(c) H2O o-nitrophenol
(d) HF p-nitrophenol
138. Intramolecular hydrogen bond exists in
(a) ortho nitrophenol (b) ethyl alcohol
(c) water (d) diethyl ether
139. The boiling point of p-nitrophenol is higher than that of
o-nitrophenol because
(a) NO2 group at p-position behave in a different way
from that at o-position.
(b) intramolecular hydrogen bonding exists in
p-nitrophenol
(c) there is intermolecular hydrogen bonding in
p-nitrophenol
(d) p-nitrophenol has a higher molecular weight than
o-nitrophenol.
140. Which one of the following is the correct order of interactions?
(a) Covalent2–
(i) There is formation of a double bond and two single
bonds.
(ii) There are two additional electrons than those
provided by the neutral atoms.
(iii) The least electropositive atom occupies the central
position in the molecule/ion.
(a) (i) and (iii) (b) (i), (ii) and (iii)
(c) (iii) only (d) (i) and (ii)
62 CHEMICAL BONDING AND MOLECULAR STRUCTURE
152. Choose the correct sequence of T and F for following
statements. Here T stands for true statement and F stands
for false statement.
(i) Formal charge in the Lewis structure helps in
keeping track of the valence electrons in the
molecule.
(ii) Formal charge indicates the actual charge separation
within the molecule.
(iii) Formal charges help in the selection of the lowest
energy structure from a number of possible Lewis
structures.
(a) T T F (b) T F T
(c) T T T (d) F T T
153. Read the following statements and choose the correct
option. Here T stands for True and F stands for False
statement.
(i) The smaller the size of the cation and the larger the
size of the anion, the greater the covalent character
of an ionic bond.
(ii) The smaller the charge on the cation, the greater the
covalent character of the ionic bond.
(iii) For cations of the same size and charge, the one,
with electronic configuration (n – 1)dnns0, typical of
transition metals, is more polarising than the one
with a noble gas configuration, ns2 np6, typical of
alkali and alkaline earth metal cations.
(a) T T T (b) T T F
(c) T F T (d) F T T
154. Choose the correct sequence of T and F for following
statements. Here T stands for True and F for False
statement.
(i) Sigma bond is formed by head on overlap of
bonding orbitals along the internuclear axis.
(ii) Pi bond is formed when atomic orbitals overlap in
such a way that their axes remain parallel to each
other and perpendicular to the internuclear axis.
(iii) Half-filled s-orbital of one atom and half filled
p-orbitals of another atom forms. bond on
overlapping.
(iv) Overlapping in case of pi-bond takes place to a
larger extent as compared to sigma bond.
(a) T T T T (b) T F T F
(c) T T F F (d) T T F T
155. Give the correct order of initials T or F for following
statements. Use T if statement is true and F if it is false :
(i) The order of repulsion between different pair of
electrons is lp – lp > lp – bp > bp – bp
(ii) In general, as the number of lone pair of electrons on
central atom increases, value of bond angle from
normal bond angle also increases
(iii) The number of lone pair on O in H2O is 2 while on N in
NH3 is 1
(iv) The structures of xenon fluorides and xenon
oxyfluorides could not be explained on the basis of
VSEPR theory
(a) TTTF (b) TFTF
(c) TFTT (d) TFFF
156. Which of the following statements is/are not correct for
combination of atomic orbitals?
(i) The combining atomic orbitals must have the same
or nearly the same energy.
(ii) Greater the extent of overlap, the greater will be the
electron density between the nuclei of a moleculer
orbital.
(iii) 2pz orbital of one atom can combine with either of
2px, 2py or 2pz orbital of other atom as these orbitals
have same energy.
(a) (i) and (ii) (b) (iii) only
(c) (i) only (d) (ii) and (iii)
MATCHING TYPE QUESTIONS
157. Match the columns
Column-I Column-II
(A) BeH2 (p) Odd electron molecules
(B) SF6 (q) Expanded octet
(C) NO2 (r) Incomplete octet of
central atom
(a) A – (p), B – (q), C – (r)
(b) A – (q), B – (r), C – (p)
(c) A – (r), B – (q), C – (p)
(d) A – (r), B – (p), C – (q)
158. Match the columns
Column-I Column-II
(A) HCl (p) Covalent compound with
directional bond
(B) CO2 (q) Ionic compound with
non-directional bonds
(C) NaCl (r) Polar molecule
(D) CCl4 (s) Non-polar molecule
(a) A – (p, q, r), B – (q, r), C – (p, q), D – (r)
(b) A – (q), B – (r), C – (p), D – (s)
(c) A – (p, r), B – (p, s), C – (q), D – (p, s)
(d) A – (q), B – (r), C – (p, q), D – (s)
159. Match Column-I with Column-II and Column-III and choose
the correct option from the given codes.
Column-I Column-II Column-III
Molecule (No. of lone (Shape of molecule)
pairs and
bond pairs)
(A) NH3 (i) 1, 2 (p) Bent
(B) SO2 (ii) 1, 4 (q) Trigonal pyramidal
(C) SF4 (iii) 2, 3 (r) T-shape
(D) ClF3 (iv) 1, 3 (s) See-Saw
(a) A – (iv, q); B – (ii, p); C – (i, r); D – (iii, s)
(b) A – (iv, q); B – (i, p); C – (ii, s); D – (iii, r)
(c) A – (i, p); B – (iii, s); C – (iv, r); D – (ii, q)
(d) A – (iv, p); B – (i, r); C – (iii, q); D – (ii, s)
CHEMICAL BONDING AND MOLECULAR STRUCTURE 63
160. Match the columns
Column-I Column-II
(A) Trigonal planar (p) PCl5
:
::
120°
A
(B) Tetrahedral (q) NH4
+
:
:
::
109.5°
A
(C) Trigonal bipyramidal (r) SF6
:
:
:
: :
90°
120°
A
(D) Octahedral (s) BF3
:
:
:
:
:
:
A
90°
90°
(a) A – (p), B – (q), C – (r), D – (s)
(b) A – (s), B – (r), C – (q), D – (p)
(c) A – (s), B – (q), C – (p), D – (r)
(d) A – (r), B – (p), C – (q), D – (s)
161. Match the columns
Column-I Column-II
(A)
+
–
+ – (p) negative overlap
(B)
+
–
+– (q) zero overlap
(C) + +– (r) positive overlap
(D) + + –
(a) A – (p), B – (q), C – (p), D – (r)
(b) A – (p), B – (r), C – (q), D – (p)
(c) A – (q), B – (q), C – (p), D – (r)
(d) A – (r), B – (p), C – (q), D – (p)
162. Match Column-I (molecule) with Column-II (type of
hybridisation) and choose the correct option from the
codes given below.
Column-I Column-II
(Molecule) (Type of hybridisation)
(A) SF6 (p) sp3d
(B) PF5 (q) sp3
(C) BCl3 (r) sp3d2
(D) C2H6 (s) sp2
(a) A – (r), B – (p), C – (s), D – (q)
(b) A – (r), B – (p), C – (q), D – (s)
(c) A – (p), B – (r), C – (q), D – (s)
(d) A – (p), B – (r), C – (s), D – (q)
163. Match the columns
Column-I Column-II
(A) Valence bond theory (p) Nyholm and Gillespie
(B) Octet rule (q) F. Hund & R. S Mulliken
(C) Molecular orbital (r) Heitler and London
theory
(D) The valence shell (s) Kossel and Lewis
electron pair
repulsion theory
(a) A – (p), B – (q),C – (r), D – (s)
(b) A – (q), B – (r),C – (s), D – (p)
(c) A – (p), B – (s),C – (q), D – (r)
(d) A – (s), B – (r), C – (q), D – (p)
164. Match the columns
Column-I Column-II Column-III
(A) 1s (p) +– +–
*2p
(i) +
–
(B) 2pz (q) +
*1s
– (ii) +– –
(C) 2px (r)
+
+
–
–
(iii) +
(a) A – (q, iii), B – (r, i), C – (p, ii)
(b) A – (q, iii), B – (p, ii), C – (r, i)
(c) A – (p, iii), B – (q, ii), C – (r, i)
(d) A – (p, ii), B – (q, iii), C – (r, i)